ADVANCED TOPICS IN RELATIONAL
DATABASES
Spring 2011
Instructor: Hassan Khosravi
AUTHORIZATION
4.2
Database Authorization
 Make sure users see only the data they are supposed to see.
 Guard the database against modifications by malicious users.
 Users have privileges

Can only operate on data for which they are authorized

Select on R

Insert on R

Update on R

Delete on R
4.3
Example
 Apply(dec), Select(Sid)
 Student select(SID,GPA)
4.4
4.5
 How can we give the following privilege

Select students info for Stanford applications only

Delete Berkeley applications only
4.6
Obtaining Privileges
 Relation creator is owner
 Owner has all privileges and may grant privileges

Grant privs on R to users

[with grant option]
4.7
Revoking Privileges
 Cascade: also revoke privileges granted from privileges being revoked
transitively, unless also granted from another source
 Restrict: disallow if cascade would revoke any other privileges
4.8
ON-LINE ANALYTICAL
PROCESSING (OLAP)
4.9
 Two broad types of database activities


OLTP: Online Transaction Processing

Short transactions

Simple queries

Touch small portion of data

Frequent updates
OLAP: Online Analytical Processing

Long transactions

Complex queries

Touch large portions of data

Infrequent updates
4.10
Data warehousing
 Bring data from operational OLPT sources into a single warehouse for
OLAP analysis
 Decision Support System

Data warehouse tuned for OLAP
4.11
Star Schema
 Fact table (relationships)

Updated frequently, very large

Sales transaction, course enrollment
 Dimension tables (entities, objects)

Stores, items, customers

Students, courses
4.12
Example
4.13
 Performance

Inherently very slow:

Special indexes

Extensive use of materialized views
4.14
DATA CUBES
4.15
Multi-dimensional OLAP
Data Cube
 Dimension data form axes of Cube
 Fact data in cells
Customers
Item
Stores
4.16
Customers
Item
Qty and price for I32, C4, s17
Stores
 Assuming one quantity for that
4.17
 Usually have defined aggregate functions that are meaningful

Sum(qty * price)
Customers
Item
Aggregate over all items for C5, s11
Stores
4.18
 Usually have defined aggregate functions that are meaningful

Sum(qty * price)
Customers
Item
Aggregate over all stores for I 61, C5, C21
Stores
4.19
 Usually have defined aggregate functions that are meaningful

Sum(qty * price)
Customers
Item
Aggregate over all customers for I 5, s13
Stores
4.20
 Usually have defined aggregate functions that are meaningful

Sum(qty * price)
Aggregate over all stores and customers for I 52
Customers
Aggregate over all stores and Items for c63
Item
Aggregate over all customers and Items for s2
Stores
4.21
 Usually have defined aggregate functions that are meaningful

Sum(qty * price)
Customers
Item
Full aggregation
Stores
4.22
Example
4.23
4.24
Drill Down
 Add for category to the group by and selection
4.25
Roll Up
4.26